I just looked at it and I don't really know what you are trying to say or accomplish. And I don't understand the significance of using a 4x4.

I don't doubt that you do though. The difference is that you are explaining how to arrive at your conclusions using your filters and verbiage and they don't fit mine.

I wouldn't understand someone that explained it using trig either.

I would understand it if it was explained using the framing square. Or, I would be able to understand what your pictures are saying if you used your pictures, then related the ratios to the framing square. With those ratios given, I'd eventually begin to understand your reason for using the 4x4.

I think my inability to grasp your drawings is due to a few different things. I don't have a 4x4 in my possession to do your drawings. I don't have a framing square to lay against the drawings to assist me in my exploration and finally, it's hard to explain things on the internet lol!

I do understand the principle that each angle is related to another angle in a roof. We were taught that principle with a 2d illustration called the "butterfly" in carpentry school. It showed how each leg of the triangles formed one leg of the other triangles involved in complex roofs.

It is an interesting tip Huck and I admire your dedication at arriving at your solution. I only offered these comments to you to address your wonder why others can't grasp it. You and I both know that it takes effort to understand these complex angles and how they relate to one another and most of us aren't willing to put in the time. Matt will figure this out and he will be better off because of your tip.

I just looked at it and I don't really know what you are trying to say or accomplish

OK, maybe I could explain it this way. You're on the jobsite, and your carpenter buddy has just cut a hip for a large roof. Because it spans quite a distance, the plans show a glue-lam for the hip. Once its cut, he realizes that because of the thickness, the hip should be "backed" or beveled on top to follow the plane of the roof. He yells over to you - Hey Jim, what's the correct angle to bevel this hip?

Or you are sheathing a roof with 2x tongue and groove because it will be exposed from below. Where the planks miter to meet over the hip, your framer cuts a 45 degree cut with his blade set at 90 degrees - and finds out its a terrible fit. You like clean framing, and want the miters to fit each other where they meet.

You're putting the fascia board on a hip roof. Its a square cut fascia, and you want the miters to be tight, because they'll show. You tack a board up to the corner, then another from the other side, to scribe a line to cut. But you think, that's a hassle, tacking two pieces of fascia up, to take them down, cut them, and put them back up. Wish there were an easier way of figuring that angle. Then you cut your miter with your blade set at 45 degrees, but you find because its a square cut fascia, not a vertical fascia, its not a true 45. Close, but just off enough to make your miter less than tight. You wish you knew what the angle is you should set your saw at when you make that miter cut.

You grab a scrap of 4x4, make a few marks on it, grab your skilsaw, and cut a piece off the corner. You now have all the answers to the above questions, in less time than it takes to paint your toenails.

And I don't understand the significance of using a 4x4.

Its a readily available scrap found on most jobsites. It could be cut from any square corner of wood, or any other suitable material.

I think my inability to grasp your drawings is due to a few different things. I don't have a 4x4 in my possession to do your drawings. I don't have a framing square to lay against the drawings to assist me in my exploration and finally, it's hard to explain things on the internet lol!

Well, there you go.

To me, it's a very simply created scale model of a hip roof, where all the angles are consistent with the actual roof, and I wonder, What could be hard to understand about that? =)

Okay....thanks for the followup explanation. I'm sorry to say that I'm no further along in my knowledge...probably because I don't have that 4x4 and saw in my hand.

I do know from experience that everytime I make a cut there are angles and bevels appearing on the drops that give us clues.

My skill with rafters and bevels is all about ratios and applying them with the framing square. So, if your 4x4 lesson culminated with "normal" ratios, then I'd probably become one of the few that grasp your concepts. A normal ratio on a 5/12 is: 5/12, 5/16.97, 12/13 etc. So, I'd be looking for ways to get my framing square laid along side of those bevels and angles to compare them to the ratios that I know exist on a 5/12. Thats' how I did it onsite when confusion struck.

I'm with you -- it doesn't translate online for me. But from what others have said here, I get the feeling that if we dragged out the old, familiar rafter square, and applied it to a block of wood, we'd get it in a heartbeat.

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On that note, just finished a sweet hip-roofed gazebo for a Buddhist center a couple of miles away (also a Nautilus-shaped walk-in outdoor shower for beside the pool -- you know these austere monks!)

One of the guys took home all of the 8x8 post offcuts, but I know he'd be happy to share them. So I'm going to get all of the guys back together to walk through and critique Huck's idea.

Full report to follow, Jim, but it might be a while -- we've all scattered to the four corners of our local job market.

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On that note, we're in SE Michigan, the worst place in all of the country. Some of us have still managed to stay busy, and pull down $40-$45/hr on our T&M jobs. And tickled pink and more than happy to pull down $25/hr on bid jobs, just to stay busy -- last Winter was scary for me, and I really had to go through the Rolodex to stay semi-busy.

Others here, out there in the auto community, are going through scary, scary times. Let's all send them good thoughts.

How are you guys out in the rest of the country doing? Hanging in there?

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Hmmm, I got a little off track there. Maybe I'll get bumped to the Tavern. If I do, I'll see you there.

I don't really even need the rafter square as much as I need to see the numbers on the angles that they are showing.

The one thing that we never see much of in SE Michigan was those style overhangs. They are a lot more common here in TX. I think I did one in West Bloomfield back in the 70's. I might have done one on a remodel in the Bloomfields in the 80's. They are just so rare there.

I do like learning about the angles and stuff (or, maybe I should say "used to" like learning LOL). I just wish he would blow up those angle on sketchup and lay a framing square on it. I'd know exactly what was going on in a minute or two.

i think i got it, that is too freaking easy man......you got any time this weekend to talk a lil about it? i got a rafter class im teaching and i think this would be a great way to show 3rd year apprentices in Framing II the other ways to skin a cat.

this is a great group of kids, very very mathematically having it together and after 7 hours they were still begging for more after day one.

maybe i can call and we can talk it over some? think that would take the gray areas out. if you dont mind email me a phone number and a time be glad to call.

Glad to hear you can use this - at one point I would have given my left ear for this information. It was a hard won battle to get to this point. Not that useful unless you're a roof cutter, 'tho, and we are a dying breed!

I get it, pretty simple.Mark the pitch off the corner of the block, set your saw at 45, cut line (one).

Thank you. So simple it's ridiculous! All the angles are there. The common, the hip / valley, the backing the fascia, the sheathing, everything. I've got roof framing books that make you jump through a bunch of hoops to get all that info. And its right there, so simple, this way.

Taking your concept to the next level is an obvious expansion of this method.Let’s apply this to irregular pitch roofs.Two pitches, two blocks/(cuts), two plan angles....

Are you following me?

(Now… nobody in their right mind is going to run fascia square to both sides of a bastard hip. (Fascia width issues)That’s not my point.But you can solve all the other pertinent data using your/the block cut method as well.)

OK, I'm working on it. You could, by the way, run a square cut fascia, it just would have to be square to one side or the other, and then you would have to compensate with the angle and width on the adjacent side. Be kind of a hassle, but it would have that tidy "tucked under" look of the square cut fascia all the way around the hip.

Here's a model for an irregular hip with a 5:12 pitch meeting a 10:12 pitch at the end of the building.

It would require two pieces to get all the angles. One side, the 5:12 pitch, would be easy. Start out just like the other one, but don't set your sawblade at 45 degrees, set it at 26.5 degrees. The tricky one is the other side, the 10:12 pitch side. Haven't got that one totally figured out yet!

I’ve got plans for the day so I won’t be able to work on this immediately.

Using Sketchup, draw two blocks and tilt/rotate them to each pitch at right angles from each other and intersect them at the imaginary hip corner.Slice through the blocks at the intersection point with a plumb plan view angle plane.(Easier said than done?)

So, assume this is a 4x4 or a 6x6. First, lay out the 5:12 side just like the model for the standard hip. But cut down line 1 at 26.5 degrees, since its an irreguar hip. You now have all the angles for half of the roof. The leftover piece will yield the remaining angles, so hang onto it.

and... you could have all the remaining angles with 6 pencil marks and 3 cuts at 90 degrees, but unless you've followed along to this point, it'll only confuse ya' to go any further! Anyone with me to this point? (the remainder is harder to explain than it is to do!)

Joe - the model gives you the angles, in a 3D model. The only angle you need to know is the roof pitch, and you don't need that in degrees, you just need to mark it accurately. Use a speed square or framing square, start with the roof pitch angle, follow the directions, and you will end up with a 3D model that has all the angles of the hip roof, in a model you can hold in your hand. Transfer them to your work with a sliding t-bevel, or just by setting your skilsaw on the model as you adjust the angle of the base plate.

Each roof pitch will produce different angles. The SketchUp drawing shows how its done - it features a 5:12 roof pitch, but the angles are not given because they will always be different with each different pitch - but the means at arriving at them is what is demonstrated, and it remains consistent.

Once you grasp how the model relates to the actual roof, then all the angles are right there. You can measure them with a protractor if you want, but why bother? That's the point of this exercise, to find the angles in 3D without math or calculators or tables or measurements in degrees.

You mentioned instructions on how to go about and layout the 4x4, but just where are these instructions found. I read the "tip blog" and didn't really see any that were "instruction like."

This is what I was reading and are these the instructions?

"Here's how it works: Angle A represents the pitch of the roof. Line 2 is drawn at 90 degrees to line 1, from the corner. It represents the run of the roof. And the green side of line 1 represents the rise of the roof.

Line 3 is drawn at the same length as line 2. Lines 4 and 5 are drawn once the length of line 3 is determined. Line 5 represents the hip rafter, as line 6 represents the common rafter.

If you cut away the dark brown portion, the piece remaining contains all the pertinent angles, in 3D, including the fascia compound miter angles, the roof sheathing compound miter angles (which are more important when working with thicker sheathing, like 2x planking), and the backing angles for hip and valley rafters."

Another thing is wouldn't one need to know which part of the 3D block (a face and a side) would go against the saw blade and saw base to form the angle you need to cut? That's why I mentioned labeling them.

Lastly the angle at "angle a", according to the model, is the seat cut angle for 5/12 roof, its complement would be the pitch angle.

Draw angle A, the pitch of the roof. Draw line 2 at 90 degrees to line 1, from the corner. It represents the run of the roof. And the green side of line 1 represents the rise of the roof.

Draw line 3 at the same length as line 2. Draw lines 4 and 5 from the end of line 3, once the length of line 3 is determined. Line 5 represents the hip rafter, as line 6 represents the common rafter.

Then cut away the dark brown portion, and the piece remaining contains all the pertinent angles, in 3D, including the fascia compound miter angles, the roof sheathing compound miter angles (which are more important when working with thicker sheathing, like 2x planking), and the backing angles for hip and valley rafters."

Another thing is wouldn't one need to know which part of the 3D block (a face and a side) would go against the saw blade and saw base to form the angle you need to cut? That's why I mentioned labeling them

Bingo! - understanding how the model relates to the actual roof is the key! That's why I posted this photo, which clarifies it. And why I tell which part of the roof each line represents. Once you grasp that, you've got all the angles covered.

edited to add: really, all you have to do is draw line one, at the angle of roof pitch, and cut along it at 45 degrees, and you've got everything. Jalapeno figured it out. But I spent a little more time describing the other lines, and how to arrive at them, and what they represent, to help visualize the way the model relates to the actual roof.